Anti-Epileptics

Question 1

Types of neurotransmitters involved in epilespy

Answer 1

GABA (inhibitory)

Glutamate (excitatory)

Question 2

Types of antiepiletic drugs

Answer 2

Na+ channel inhibitors

Barbituates

Benzodiazepines

Ca+ channel blockers

Question 3

Na+ channel inhibitors mechanism of action and examples

Answer 3

Act by blocking voltage gated sodium channels by selectively binding the channel in the inactive state. This slows the spread of electrical activity.

Phenytoin, fosphenytoin, carbamzepine, oxcarbazepine, valproic acid, lamotrigine, topiramate, zonisamide

Question 4

Phenytoin drug class and indications

Answer 4

Sodium channel inhibitor

Firstline for partial and generalized tonic-clonic seizures

Some efficacy in clonic, myoclonic and atonic seizures

Question 5

Phenytoin adverse drug reactions

Answer 5

Gingival hyperplasia, hirsutism, acne

• fetal hydantoin syndrome

Question 6

Carbamazepine drug class and adverse drug reactions

Answer 6

Sodium channel inhibitor

Diplopia, ataxia, GI upset, sedation, water retention and hyponatremia, rash, agitation, idiosyncratic blood dyscrasias and severe rash

Question 7

Lamotrigine indications and adverse effects

Answer 7

Sodium channel inhibitor

Used in epilepsy and bipolar disorder

Dizziness, drowsiness, headache, blurred vision

Question 8

Valproic acid mechanism of action and indications

Answer 8

Mixed: Sodium channel inhibitor, some Ca+ channel inhibition, and increases GABA

Used for simple, complex partial, primary generalized tonic-clonic, absence, myoclonic and atonic seizures

Question 9

Valproic acid adverse effects and contraindications

Answer 9

Weight gain, tremor, transient hair loss, PCOS and menstrual disturbance, bone loss, ankle swelling

Contraindicated in liver disease

Question 10

Topiramate mechanism of action and indications

Answer 10

Mixed: Sodium channel inhibitor, enhances GABA

Used as an adjunct therapy in partial and primary generalized seizures. Decreases tonic and atonic seizures in children with Lennox-Gastaut syndrome. Can be used in adults and children over age of 2.

Question 11

Topiramate adverse effects

Answer 11

Nervousness, paresthesias, psychomotor slowing, difficulty word finding, impaired concentration and memory,

Question 12

GABA Mechanism of Action

Answer 12

Neurotransmitter that inhibits neural excitation.

Question 13

Drugs that enhance GABA

Answer 13

Benzodiazepines

Barbiturates

Question 14

Barbiturate Mechanism of Action and Examples

Answer 14

Phenobarbital (Luminal), Primidone (Mysoline)

Increases the duration of GABA activated Cl- channel opening

Question 15

Phenobarbital indications and contraindications

Answer 15

Indications: status epilepticus, second-line for partial and generalized tonic clonic seizures

Can have cognitive effects, generally avoided in older children and adults.

Contraindications: Absence seizure

Question 16

Barbiturate Adverse Effects

Answer 16

Dependence, agitation and confusion (esp. in elderly), worsening aggression and hyperactivity, sexual side effects.

Question 17

Benzodiazepine Mechanism of Action and Examples

Answer 17

Diazepam, lorazepam, clonazepam, clorazepate

Increases the frequency of GABA activated Cl- channels.

Question 18

Benzodiazepine indications and containdications

Answer 18

Indications: Status epilepticus treatment, control of seizure clusters (diazepam)

Contraindicated in narrow angle glaucoma.

Question 19

Benzodiazepines Adverse Effects

Answer 19

Hypotonia, dysarthria, impaired muscle co-ordination, behavioral changes, dependence.

Question 20

Gabapentin Mechanism of Action and Indications

Answer 20

Inhibits Na+ and Ca+ channels

Uses: Adjunct therapy for partial and secondary generalized seizure, post herpetic neuralgia

Off label: fibromyalgia, migraine, psych disorders

Question 21

Gabapentin Adverse Effects

Answer 21

Weight gain, ankle edema, irritability, possible movement disorders with prolonged use